scholarly journals Dielectric properties of Bi12SiO20 crystals doped with Al

2019 ◽  
Vol 27 (2) ◽  
pp. 85-88
Author(s):  
T. V. Panchenko ◽  
L. M. Karpova
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
Hysteresis Loops ◽  
Complex Dielectric Permittivity ◽  
Temperature Range ◽  
Dielectric Matrix ◽  
Before And After ◽  
Frequency Dependences

The temperature-frequency dependences of the complex dielectric permittivity ε and the voltage-farad characteristics of undoped and aluminum doped Bi12SiO20 crystals are studied before and after their polarization. It is shown that Al ions in the Bi12SiO20 dielectric matrix provide a significant increase as well as nonlinearity of ε in the temperature range 300 – 800 K and electric field strengths Е = 103 – 104 V/cm. It is shown that polarization causes the appearance of dielectric hysteresis loops. Al impurity significantly affects the appearance and parameters of these loops. The role of Al ions in increasing the contribution of the quasi-dipole mechanism in the polarization processes is revealed.

Magnetic Nanocomposites Based on Opal Matrices

2018 ◽  
Vol 781 ◽  
pp. 149-154 ◽  
Author(s):  
Alexey Belyanin ◽  
Alexander Bagdasarian ◽  
Sergey Bagdasarian ◽  
Petr Luchnikov ◽  
Natalya Katakhova
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Constant ◽  
Hysteresis Loops ◽  
Lattice Packing ◽  
Magnetic Nanocomposites ◽  
Multiferroic Materials ◽  
X Ray ◽  
Temperature Range ◽  
Frequency Dependences

Features of obtaining magnetic nanocomposites based on the lattice packing of SiO2 nanoscale (opal matrices) with clusters of multiferroic materials (Li-Zn, Bi, Fe, Dy, Gd and Yb titanates) in their interstitial cavities have been considered. For magnetic nanocomposites creation opal matrices with SiO2 nanoscale of ~ 260 nm in diameter have been used. The composition of nanocomposites has been also studied using X-ray diffractometry and Raman spectroscopy. The results of the frequency dependences measurement for the dielectric constant of the nanostructures obtained have been presented. Hysteresis loops have been examined for the samples obtained in the temperature range from 2 to 400 K.

Dielectric Properties of Dielectrophoretically Aligned ZnO-PDMS Composites

2016 ◽  
Author(s):  
Md Abdulla Al Masud ◽  
Zoubeida Ounaies
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
Mechanical Analysis ◽  
High Yield ◽  
Chemical Route ◽  
Random Composites ◽  
Pdms Elastomer ◽  
Random Dispersion ◽  
Zno Rods

ZnO based polymer composite materials are of great interest because of their excellent electrical, optical, semiconductor and biocompatible properties. In this study, we synthesize anisotropic composites of aligned ZnO rods in polydimethylsiloxane (PDMS) elastomer and study their dielectric properties as a function of applied electric field and frequency. Submicron ZnO rods are synthesized using an inexpensive, high yield chemical route. Washed and purified ZnO rods are then aligned in uncured PDMS at different electric field and frequency. We find that under electric field, ZnO rotates with their long axis in the direction of the electric field and before coalescing form chains in the silicone elastomer. From the optical microscopy images and in situ dielectric measurements, the best alignment parameters are found at 4 kV/mm and 10 kHz. These conditions are then selected to prepare aligned ZnO-PDMS composites. Complete curing of composites is confirmed using dynamic mechanical analysis (DMA). Our results show that aligned ZnO in uncured PDMS exhibit higher dielectric permittivity compared to random dispersion with the same composition. For the cured ZnO-PDMS composites, dielectric permittivity increases by 80% compared to random composites.

scholarly journals Dielectric Properties of Ternary ( ) ( )x ( ) x ZnO MgO PO 30 2 5 70− (x = 5, 8, 13) Glasses

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
S. F. Khor ◽  
Z. A. Talib ◽  
W. M. Daud ◽  
H. A. A. Sidek ◽  
W. M. M. Yunus ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Empirical Data ◽  
Loss Factor ◽  
Low Frequency ◽  
Frequency Range ◽  
Melt Quenching ◽  
Dipolar Relaxation ◽  
Temperature Range

(ZnO)30(MgO)x(P2O5)70-x glasses of the composition x = 5, 8 and 13 mol % have been prepared by melt quenching technique. The dielectric permittivity (89) and loss factor (8:) were measured in the frequency range from 0.01 Hz to 1 MHz and in the temperature range 303 to 573 K . From the results there are evidence of dipolar relaxation occurring between 103 – 106 Hz while at low frequency the spectrum is dominated by dc conduction which manifested by the 1/@ slope of loss factor plot. Value of the relaxing frequency (@p) plotted against 1/T shows one electrical transportation mechanism. The empirical data was sufficiently fitted by using Harviliak-Negami equation.

scholarly journals Investigation of dielectric properties in tantalum doped AgNbO3 ceramic

2021 ◽  
Vol 2070 (1) ◽  
pp. 012058
Author(s):  
A Joshi ◽  
S C Bhatt ◽  
M Uniyal ◽  
K Kumar
Keyword(s):  
Dielectric Properties ◽  
Phase Shift ◽  
Low Temperature ◽  
Electric Field ◽  
Dielectric Materials ◽  
Major Effect ◽  
Temperature Range ◽  
Electronic Technologies

Abstract Dielectric materials developed from Tantalum (Ta) doped AgNbO3 (ATN) show excellent properties in variety of electronic technologies. In the temperature range of 70 to 400 °C, four major dielectric abnormalities were observed in ATN (x = 0.1) while in ATN (x = 0.2) the maxima of M1-M2 phase shift to low temperature value. ATN ceramics’ dielectric properties dominate temperature and electric field-based performance, which has a major effect on their properties. This study looked into the dielectric properties in ATN.

Dielectric and electrical properties of near-surface layers of TlInS2 crystals under the proton irradiation

2019 ◽  
Vol 33 (27) ◽  
pp. 1950320
Author(s):  
S. F. Samadov ◽  
O. A. Samedov ◽  
O. Z. Alekperov ◽  
M. Kulik ◽  
A. I. Najafov ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Proton Irradiation ◽  
Frequency Range ◽  
Surface Layers ◽  
Dielectric Parameters ◽  
Near Surface ◽  
The Real ◽  
Temperature Range ◽  
Before And After

In this work, the dielectric and electrical properties of TlInS2 crystal have been studied in the temperature range of 300–550 K before and after being implanted with H[Formula: see text] ion. The dielectric parameters such as the real and imaginary parts of permittivity, impedance and dielectric loss have been investigated in this temperature range. The role of free ions in the relaxation process when f [Formula: see text] 10 kHz on the basis of the study of dielectric parameters in the frequency range of 25–106 Hz has been determined. It has been observed that the interdependencies of the real and imaginary parts of dielectric permittivity go beyond the standard.

Permittivity and Microstructure of (Ba,Sr)TiO3 Films: Temperature and Electric Field Response

1999 ◽  
Vol 603 ◽  
Author(s):  
Yu.A. Boikov ◽  
T. Claeson ◽  
Z. Ivanov ◽  
E. Olsson
Keyword(s):  
Phase Transition ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
Single Crystal ◽  
Temperature Dependence ◽  
Transition Point ◽  
Phase Transition Point ◽  
Bulk Single Crystal ◽  
Temperature Range ◽  
Field Response

AbstractEpitaxial heterostructures (001)(Y,Nd)Ba2Cu3O7-δ∥(100)SrTiO3∥(001)(Nd,Y)Ba2Cu3O7-δ,(100)SrRuO3∥(100)Ba0.8Sr0.2TiO3∥(100)SrRuO3, (100)SrRuO3∥(100)SrTiO3∥(100)SrRuO3 and (100)SrTiO3∥(001)YBa2Cu3O7-δ have been grown by laser ablation. There was only a small difference of the dielectric permittivity, in the temperature range 180-300K, between a bulk single crystal and an epitaxial (100)SrTiO3 layer inserted between either high-Tc superconducting or SrRuO3 electrodes. At T<1 50K, on the other hand, the response of the dielectric permittivity of the SrTiO3 layer on temperature or electric field depended to a large extent upon the materials used as bottom and top electrodes in the heterostructures. The temperature dependence of the dielectric permittivity for the SrTiO3 layer in (100)SrRuO3∥(100)SrTiO3∥(100)SrRuO3 was well extrapolated by a Curie-Weiss relation in the range of T=80-300K, with about the same Curie constant (C0=7.5 × 104 K) and Curie temperature (TCurie=21K) as in a bulk single crystal. At temperatures higher the phase transition point (65 K), the electric field response of the permittivity of the SrTiO3 layer between high-TC superconducting or metallic oxide electrodes was well extrapolated by the same relation used for a bulk single crystal. The smallest loss factor, tanδ, was measured for the capacitance (100)SrRuO3∥(100)SrTiO3∥(100)SrRuO3 (T ≈ 50-300K, f=100kHz). The measured conductance G for the SrTiO3 layer in the (001)(Y,Nd)Ba2Cu3O7-δ heterostructure fitted well the relation InG∼-(ED/kT), with ED=0.08-0.09 eV in a temperature range close to 300K. Pronounced hysteresis was observed in the temperature dependence of the dielectric permittivity for the (100)Ba0.8Sr0.2TiO3 layer at temperatures close to the phase transition point, like in the case of a bulk single crystal. The permittivity of the (100)Ba0.8Sr0.2TiO3 layer decreased more than 50% when an electric field of 2.5×106V/m (T ≈ 300K, f=100 kHz ) was applied.

scholarly journals Open-Ended Coaxial Probe Measurements of Complex Dielectric Permittivity in Diesel-Contaminated Soil during Bioremediation

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6677
Author(s):  
Andrea Vergnano ◽  
Alberto Godio ◽  
Carla Maria Raffa ◽  
Fulvia Chiampo ◽  
Jorge A. Tobon Vasquez ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Moisture Content ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Complex Dielectric Permittivity ◽  
Imaginary Component ◽  
Real Component ◽  
The Real ◽  
Coaxial Probe

In the bioremediation field, geophysical techniques are commonly applied, at lab scale and field scale, to perform the characterization and the monitoring of contaminated soils. We propose a method for detecting the dielectric properties of contaminated soil during a process of bioremediation. An open-ended coaxial probe measured the complex dielectric permittivity (between 0.2 and 20 GHz) on a series of six soil microcosms contaminated by diesel oil (13.5% Voil/Vtot). The microcosms had different moisture content (13%, 19%, and 24% Vw/Vtot) and different salinity due to the addition of nutrients (22 and 15 g/L). The real and the imaginary component of the complex dielectric permittivity were evaluated at the initial stage of contamination and after 130 days. In almost all microcosms, the real component showed a significant decrease (up to 2 units) at all frequencies. The results revealed that the changes in the real part of the dielectric permittivity are related to the amount of degradation and loss in moisture content. The imaginary component, mainly linked to the electrical conductivity of the soil, shows a significant drop to almost 0 at low frequencies. This could be explained by a salt depletion during bioremediation. Despite a moderate accuracy reduction compared to measurements performed on liquid media, this technology can be successfully applied to granular materials such as soil. The open-ended coaxial probe is a promising instrument to check the dielectric properties of soil to characterize or monitor a bioremediation process.

scholarly journals Mechanisms of electrical polarization of disordered systems based on Al-substituted LiFe-oxospinel

2021 ◽  
Vol 22 (2) ◽  
pp. 336-340
Author(s):  
A.V. Vakalyuk ◽  
V.M. Vakalyuk ◽  
M.I. Hasiuk ◽  
I.M. Hasiuk
Keyword(s):  
Impedance Spectroscopy ◽  
Dielectric Permittivity ◽  
Low Temperatures ◽  
Disordered Systems ◽  
Aluminum Content ◽  
Electric Polarization ◽  
Electrical Polarization ◽  
Temperature Range ◽  
Conductive Properties ◽  
Frequency Dependences

The temperature-frequency dependences of the dielectric  permittivity and conductivity of Li2O-Fe2O3-Al2O3 ceramics in the temperature range of 298-648 K were obtained by impedance spectroscopy. Their analysis indicates the presence of a fractal-like structure in the studied samples, the effect of which is manifested at low temperatures. To study the phenomenon of electric polarization associated with this structure, we used the generalized law of Jonscher. A significant dependence of the dispersion of dielectric and conductive properties of these spinel ceramics on the temperature and aluminum content in them was revealed.

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